Basic LTE Tutorial

Objective

This tutorial presents a simple example of manually connecting LTE UE device to LTE basestation. It will use two nodes in the main ORBIT grid equipped with Netgear AC341u LTE dongles to connect to the same LTE basestation and then measure the throughput between them by runing iperf client and server.

Prerequisites

This tutorial series assumes you have an ​ORBIT account, have ​scheduled a session on the ORBIT testbed, are familiar with ​SSH'ing into the testbed itself, and are familiar with the ​basics of running ORBIT experiments. If you have not done these things yet, you may wish to do so before taking a look at this slightly more advanced experiment. If you are unfamiliar with or are entirely new to ORBIT, you may wish to start ​here.

Login into reserved domain

During your approved time slot, you will be able to ssh into the console of the respective domain. A console is a dedicated machine that allows access to all resources in that domain.

For example, to access the sandbox1:

yourhost>ssh username@console.sb1.orbit-lab.org
Using username "username".
Authenticating with public key "xxxxxxxxx"
Welcome to Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-36-generic x86_64)
* Documentation: https://help.ubuntu.com/
System information as of Mon Jan 28 20:25:50 EST 2013
System load: 0.0 Processes: 93
Usage of /: 2.7% of 69.43GB Users logged in: 0
Memory usage: 6% IP address for eth0: 10.50.18.10
Swap usage: 0% IP address for eth1: 10.18.0.10
Graph this data and manage this system at https://landscape.canonical.com/
9 packages can be updated.
0 updates are security updates.
|-----------------------------------------------------------------|
| *** For authorized use only *** |
| This system is for the use of authorized users only. All users |
| are expected to comply with the "Acceptable Use Policy" availa- |
| ble at http://www.orbit-lab.org/AUP.html |
| Individuals using this computer system, are subject to having |
| all of their activities on this system monitored and recorded |
| by system personnel. |
| |
| Anyone using this system expressly consents to such monitoring |
| and is advised that if such monitoring reveals possible |
| evidence of criminal activity, system personnel may provide the |
| evidence of such monitoring to law enforcement officials. |
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| Email question, comments or problems to help@orbit-lab.org |
|-----------------------------------------------------------------|
username@console.sb1:~$

Individual nodes are identified in the output of stat command by their fully qualified domain name (FQDN). This establishes their "coordinates" and the "domain" to which they belong. Nodes in different domains typically can NOT see each other. Node can be in 1 of 3 states:

Two important arguments are TOPOLOGY describing the set of nodes one wishes to image , and !IMAGE specifying the name of the image one wants to load the nodes with. If the imaging process does not does not finish within the default timeout period, that period can be increase by using the -o flag (e.g. -o 1600).
Typical command to load both nodes of sandbox 1 with the baseline? image would look like:

If the node is in the NOT REGISTERED state, you may need to wait for it to recover the POWEROFF state (it some times requires a few moments for the services to sync up). If the node takes more than 60 seconds to come out of the NODE NOT AVAILABLE state please report it to an administrator.

Connect to the node

Wait for nodes to boot up (30-40 seconds) and then ssh into them (don;t forget that, in case of baseline image, you are accessing nodes as 'root' user without password e.g.:

ssh root@node1-7

Loading the driver

By default in the baseline ORBIT image does not enable any wireless devices. Therefore, the first thing when manually configuring the device is to load drivers; the following 2 lines will load the Sierra wireless Netgear LTE dongle drivers:

modprobe GobiSerial
modprobe GobiNet

Connecting to the device

Control of the device is done over the serial port that is created by the driver (in this case /dev/ttyUSB1) through a sequence of AT commands and you can use your favorite serial port communication program to talk to it; in this tutorial we will use Minicom. To start to program execute:

minicom -D /dev/ttyUSB1

Managing the LTE connection

Once in minicom, one can issue series of commands to the LTE modem typically consisting of: